PVS-RIPO is an oncolytic poliovirus (PV) recombinant. It consists of the live attenuated type 1 (Sabin) PV vaccine containing a foreign internal ribosomal entry site (IRES) of human rhinovirus type 2 (HRV2). The IRES is a cis-acting genetic element located in the 5′ untranslated region of the PV genome, mediating viral, m7G-cap-independent translation. The virus has shown exciting signs of efficacy in humans Nonetheless there is a continuing need in the art to identify and develop anti-cancer treatments that are more effective and that are effective for more humans, particularly for patients with brain tumors.